1. Field of the Invention
The present invention relates to a plasma display device, and more particularly, to a plasma display device in which the brightness of a blue pixel is improved.
2. Description of the Related Art
In general, a plasma display device for displaying an image utilizing a gas discharge is widely known as a display device that may replace the CRT (cathode ray tube) due to its superior display capabilities such as display size, brightness, contrast, afterimage, and viewing angle. In the plasma display device, an DC or AC voltage is applied to electrodes, and a gas discharge occurs between the electrodes. Then, ultraviolet rays are emitted to excite phosphors and emit light.
FIG. 1 is an exploded perspective view showing the structure of a common AC type plasma display device. Referring to the drawing, a first electrode 13X, which is a common electrode, and a second electrode 13Y, which is a scan electrode, are provided in pairs on an inner surface of a front glass substrate 11. A third electrode 13A, which is an address electrode is located on an inner surface of a rear glass substrate 12. The first electrode 13X and the second electrode 13Y, and the third electrode 13A are strips on the inner surface of the front glass substrate 11 and the rear glass substrate 12, respectively, such that they cross perpendicularly when the two substrates 11 and 12 are assembled. A dielectric layer 14 and a protective layer 15 are sequentially deposited on an inner surface of the front glass substrate 11. A plurality of partitions 17 on the upper surface of a dielectric layer 14xe2x80x2 forming a cell 19 between neighboring partitions 17. The cell 19 is filled with inert gas such as argon (Ar). Also, a side surface of the cell 19 is coated with a phosphor 18. Respective cells 19 correspond to pixels producing red (R), green (G) or blue (B) light and are respectively and is coated with phosphors producing corresponding to each color. A bus electrode (not shown) can be provided to enhance the function of the first electrode 13a in another example.
In the operation of the plasma display device having the above structure, a high voltage, that is, a trigger voltage, is applied to cause a discharge between the first electrode 13X and the third electrode 13A. As cations are accumulated in the dielectric layer 14 by the trigger voltage, a discharge occurs. When the trigger voltage exceeds a threshold voltage, argon gas in the cell 19 changes to a plasma so that a discharge between the neighboring first and second electrodes 13X and 13Y can be stably maintained. In the stable discharge ultraviolet rays in the discharge collide with the phosphor 18 which emits light. Thus, each pixel formed by the cell 19 can display an image.
In the above display device, the structure of all pixels is identical and thus the sustaining discharge condition for each cell is the same. As the discharge condition is the same, the brightness of each pixel is proportional to the efficiency of light emission of the phosphor. Actually, the efficiency of light emission of a blue phosphor is the lowest. Thus, when red, green and blue phosphors are excited to emit light under the same conditions, the brightness of the blue pixel is the lowest. Consequently, a white balance white by mixing red, green, and blue colors together cannot be achieved.
According to the conventional technology, to represent white balance, the brightness of red and green cells are lowered to correspond to the level of the brightness of the blue cell by using circuitry decreasing the number of discharge sustaining pulses. However, this method only manages the balance by an overall reduction in the brightness. Therefore, it is a disadvantage in the conventional technology that the overall brightness is lowered.
To solve the above problem, it is an objective of the present invention to provide a plasma display device having improved brightness.
It is another objective of the present invention to provide a plasma display device in which the brightness of a blue pixel is improved.
Accordingly, to achieve the above objective, there is provided a plasma display device which comprises a front substrate, first and second electrodes formed in parallel on an inner surface of the front substrate, a first dielectric layer formed on the inner surface of the front substrate to cover the first electrode, a rear substrate disposed to face the front substrate, a third electrode formed on an inner surface of the rear substrate to cross the first and second electrodes perpendicularly, a second dielectric layer formed on the inner surface of the rear substrate to cover the third electrode, a partition forming a discharge space above the dielectric layer of the rear substrate, and a phosphor coated on a side surface of the partition corresponding to red, green or blue. In the plasma display device, the width of the first or second electrode at the position corresponding to a discharge space coated with the blue phosphor, extending toward a region where light is not emitted, is formed to be greater than that of each of the first and second electrodes at the position corresponding to a discharge space coated with the red or green phosphor.
It is preferred in the present invention that the distance between the first electrode and the second electrode at the position corresponding to a discharge space coated with the blue phosphor is formed to be narrower than that of the first electrode and the second electrode at the position corresponding to a discharge space coated with the red or green phosphor.
Also, it is preferred in the present invention that the first dielectric layer of the front substrate at the position corresponding to a discharge space coated with the blue phosphor is formed to be thinner than the area of the first dielectric layer corresponding to a discharge space coated with the red or green phosphor.